Conjugated polymers and nanocrystal quantum dots (“QDs”) have attracted the attention of researchers for the development of novel optoelectronic devices, such as light emitting diodes (“LEDs”), photovoltaics, and optical information memory. The tunable band gap of QDs makes them attractive for tailoring the visible and infrared absorption and emission of the light-sensitive layer of optoelectronic devices. Both conjugated polymers and nanocrystals are promising candidates for novel optoelectronic devices also because of their simple chemical syntheses and the easy processing methods such as spin-coating or doctor-blading.
Optoelectronic devices made of pure poly[2-methoxy-5-(2′-ethylhexyloxy)-1,4-phenylenevinylene] (“MEH-PPV”), such as those disclosed in U.S. Pat. No. 5,189,136 to Wudl and Srdanov, have limited quantum efficiencies due to a low electron and hole mobility compared to those of inorganic materials, L. Bozano, et al., Appl. Phys. Lett., 74, 1132 (1999). J. S. Steckel, et al., disclose infrared electroluminescent devices having colloidally grown PbSe quantum dots (QDs) in organic host materials. The electroluminescence is tuned from a wavelength (λ, lambda) of 1.33 microns (1330 nm) to 1.56 microns (1560 nm) by changing the quantum dot size. U.S. Pat. App. Pub. No. 2005/0002635 discloses a composite material comprising a host material in which are incorporated semiconductor nanocrystals.
Accordingly, there is a continuing need to prepare optoelectronic materials for use in optoelectronic devices, such as light emitting diodes, photovoltaic cells, lasers and photodetectors. In particular, there is a continuing need to develop optoelectronic materials having quantum efficiencies greater than 1.